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Open Access

Turbo-per-Tone Equalization for ADSL Systems

EURASIP Journal on Advances in Signal Processing20052005:581826

Received: 9 October 2003

Published: 15 May 2005


We study the equalization procedure in discrete multitone (DMT)-based systems, in particular, in DMT-based ADSL systems. Traditionally, equalization is performed in the time domain by means of a channel shortening filter. Shifting the equalization operations to the frequency domain, as is done in per-tone equalization, increases the achieved bitrate by 5–10%. We show that the application of the turbo principle to per-tone equalization can provide significant additional gains. In the proposed receiver structure, referred to as a "turbo-per-tone equalization" structure, equalization and decoding are performed in an iterative fashion. Equalization is done by means of a linear minimum mean squared error (MMSE) equalizer, using a priori information. We give a description of an efficient implementation of such an equalizer in the per-tone structure. Simulations show that we obtain a bitrate increase of 12–16% compared to the original per-tone equalization-based receiver structure.

Keywords and phrases

ADSLmulticarrier modulationturbo equalization

Authors’ Affiliations

ESAT/SCD, Katholieke Universiteit Leuven, Heverlee, Belgium


© H. Vanhaute and M. Moonen 2005

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.